removed — the implementation has been removed from the repository, and the eclasses ignore its occurences in PYTHON_COMPAT. It is no longer possible to us, it should be removed from your system ASAP and you can drop it from PYTHON_COMPAT at will with no worries.

deprecated — the implementation is no longer supported and will be removed at some point. You should avoid adding support for it to more packages. However, please avoid removing it from PYTHON_COMPAT since that can cause dependency errors.

supported — the implementation is currently supported. We're happy to handle bugs, add support for it, etc. Developers are encouraged to test their packages with all supported implementations.

current stable — the implementation is supported and enabled by default for our users. The developers are expected to test their packages with all implementations qualified as this.

experimental — the work on supporting the implementation is ongoing. It is not ready for wide use yet but developers may already start testing their packages with it.

future — the implementation will be supported in the future. The implementation name is reserved already, and the eclass may have partial support for it. However, ebuilds are not allowed to enable it yet.